The Effect of School Bullying Victimization on Non-Suicidal Self-Injury: The Dual Mediating Effects of Traumatic Distress and Depression–Anxiety

This study aimed to examine the dual mediating effects of traumatic distress and depression–anxiety in the relationship between experiences of school bullying victimization and non-suicidal self-injury (NSSI). Data were drawn from the 2021 National Survey on Mental Health of Adolescents conducted by the National Youth Policy Institute of Korea. The results showed that experiences of school bullying victimization were significantly and positively associated with traumatic distress, depression–anxiety, and NSSI. In addition, bullying victimization significantly increased levels of traumatic distress and depression–anxiety, and depression–anxiety significantly predicted NSSI. In contrast, the direct effect of traumatic distress on NSSI was not statistically significant. Analyses of indirect effects revealed a significant single mediation pathway in which bullying victimization influenced NSSI through depression–anxiety, as well as a significant sequential dual mediation pathway whereby bullying victimization increased traumatic distress, which subsequently elevated depression–anxiety, ultimately leading to NSSI. However, the single mediation pathway from bullying victimization to NSSI through traumatic distress alone was not significant. These findings suggest that traumatic distress following school bullying victimization does not directly lead to self-injurious behavior but rather increases the risk of NSSI by intensifying internalizing symptoms such as depression and anxiety. The results underscore the importance of assessing trauma-related responses and negative emotional states among adolescents exposed to school bullying and highlight the need for emotion-regulation–focused interventions for the prevention of non-suicidal self-injury.